A reactor is one of the components of a circuit that performs a voltage step up or step down operation. The reactor is used for a converter mounted on a vehicle such as a hybrid vehicle. The reactor is disclosed in, for example, Patent Literature 1.
The reactor disclosed in Patent Literature 1 has the structure in which a combined product made up of a coil and a magnetic core is stored in a case. The coil is formed by a wound wire being a rectangular wire. The magnetic core includes a circular cylindrical inner core portion disposed inside the coil, and a coupled core portion (an outer core portion) that is formed by a molded composite material which is a mixture of magnetic substance powder and resin, the coupled core portion being disposed at the outer circumference of the coil. Patent Literature 1 discloses formation of an inner resin portion (a mold resin portion) made of an insulating resin on the surface of the coil, which secures insulation between the coil and the magnetic core.
In connection with the reactor of Patent Literature 1, in the magnetic core, the outer core portion disposed at the outer circumference of the coil is formed by the composite material of magnetic substance powder and resin. Other known mode of the reactor includes the structure in which a combined product, in which a coil is disposed at an annular magnetic core, is stored in a case. The surrounding of the combined product (a coil) is sealed by a sealing resin by potting. In other structure, the surrounding of the combined product (the coil) is molded by a sealing resin using a mold assembly, thereby achieving sealing (e.g., see Patent Literature 2).